Effects of clinical dental implant abutment materials and their surface characteristics on initial bacterial adhesion

Initial bacterial adhesion on dental implant abutment is related to its surface chemical composition and physical characteristics. Selection of appropriate abutment materials resistant to bacterial adhesion is important for dental implant maintenance. The aim of present study was to evaluate the effect of different properties of abutment materials on initial bacterial adhesion in vitro. Polished zirconia (PZ group), polished titanium (PT group) and ground titanium (GT group) samples were prepared to simulate clinical dental implant abutments. Chemical compositions, morphology, roughness, hydrophilicity and surface free energy of materials were analyzed. Oral commensal bacterium Streptococcus mitis was used to evaluate initial bacterial adhesion via turbidity test and colony-forming unit counting. The results showed that GT group presented the highest roughness, hydrophilicity and surface free energy. After 6-h incubation, GT group showed the significantly highest adhered bacteria counts; while non-significant difference existed between PT and PZ groups. Within the clinically applicable range used in present study, the surface physical characteristics, instead of surface chemical composition, of dental abutment material have the pronounced influence on initial 6-h bacterial adhesion.